The subject matter of the present disclosure broadly relates to the art of gas spring devices and, more particularly, to an end member for use in forming a gas spring assembly. A gas spring assembly including such an end member and a suspension system including one or more of such gas spring assemblies are also included. Additionally, an end member assembly including such an end member and a cover therefor is also included.
The subject matter of the present disclosure may find particular application and use in conjunction with components for wheeled vehicles, and will be shown and described herein with reference thereto. However, it is to be appreciated that the subject matter of the present disclosure is also amenable to use in other applications and environments, and that the specific uses shown and described herein are merely exemplary. For example, the subject matter of the present disclosure could be used in connection with gas spring assemblies of non-wheeled vehicles, support structures, height adjusting systems and actuators associated with industrial machinery, components thereof and/or other such equipment. Accordingly, the subject matter of the present disclosure is not intended to be limited to use associated with gas spring suspension systems of wheeled vehicles.
Wheeled motor vehicles of most types and kinds include a sprung mass, such as a body or chassis, for example, and an unsprung mass, such as two or more axles or other wheel-engaging members, for example, with a suspension system disposed therebetween. Typically, a suspension system will include a plurality of spring devices as well as a plurality of damping devices that together permit the sprung and unsprung masses of the vehicle to move in a somewhat controlled manner relative to one another. Movement of the sprung and unsprung masses toward one another is normally referred to in the art as jounce motion while movement of the sprung and unsprung masses away from one another is commonly referred to in the art as rebound motion.
Generally, the range of motion of a suspension system extends between a first or fully compressed condition and a second or fully extended condition. To retain the one or more gas spring assemblies in operative association the sprung and unsprung masses, each end of the one or more gas spring assemblies is typically secured on or along opposing structural members of the associated sprung and unsprung masses (e.g., opposing components of a suspension system). As such, conventional gas spring end members are often constructed to withstand forces and loads acting on the gas spring assembly that are transmitted to, from and/or between the opposing structural members of the associated sprung and unsprung masses. Additionally, conventional gas spring end members are often constructed to withstand conditions associated with use in operation during over-the-road travel and/or under similar environments, such as impacts from rocks and debris and the collection of dirt.
In some cases, however, it may be desirable to reduce the overall weight of a vehicle suspension system. Reducing the weight of the end members of the one or more gas spring assemblies can be one contributing factor to achieving such a goal. In some cases, known end member designs have been formed from a polymeric material to contribute to reduced suspension system weight. Such polymeric materials can include, without limitation, glass or other fiber-reinforced polypropylene, glass or other fiber-reinforced polyamide, for example, and high-strength (unfilled) thermoplastics, such as polyester, polyethylene, and other polyether-based materials, or any combination thereof.
As one example, an end member may include an inner wall that encloses a volume or chamber in communication with a volume or chamber formed by a flexible wall of the gas spring assembly. In many cases, an outer wall will generally surround the inner wall. In such cases, the flexible wall of the gas spring assembly can form a rolling-lobe that is displaced along an outer surface of the outer wall as the gas spring assembly undergoes changes in overall height. For example, variations in forces and/or load conditions applied to the suspension system will result in greater or lesser portions of the outer wall being covered by the flexible wall.
In many cases, extending between the inner chamber wall and the outer wall of the end member are one or more circumferentially spaced ribs. Each rib may extend over a substantial height of a radial gap between the inner wall and the outer wall, or in other instances the rib may extend over only a portion of the height. Reducing the thickness of the inner wall and/or outer wall, as well as one or more the ribs, is one way to reduce overall weight of the end member. In many cases, however, there may be a corresponding loss in strength, rigidity and/or overall robustness of the end member that is associated with such reductions, and such loss may be undesirable.
Notwithstanding the widespread usage and overall success of the wide variety of end member designs that are known in the art, it is believed that a need exists to meet these competing goals while still retaining comparable or improved performance, ease of manufacture, ease of assembly, and/or the ability to withstand impacts and reduce the collection of materials without adversely affecting the strength, rigidity, robustness and/or overall integrity of the gas spring assembly.